Skip default categories when getting known categories.

base/debug/trace_event_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/debug/trace_event_impl.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/debug/leak_annotations.h"
@@ skipping 56 matching lines @@
   "tracing already shutdown",
   "tracing categories exhausted; must increase TRACE_EVENT_MAX_CATEGORIES",
   "__metadata",
 };
 
 // The enabled flag is char instead of bool so that the API can be used from C.
 unsigned char g_category_enabled[TRACE_EVENT_MAX_CATEGORIES] = { 0 };
 const int g_category_already_shutdown = 0;
 const int g_category_categories_exhausted = 1;
 const int g_category_metadata = 2;
-int g_category_index = 3; // skip initial 3 categories
+const int g_num_builtin_categories = 3;
+int g_category_index = g_num_builtin_categories; // Skip default categories.
 
 // The name of the current thread. This is used to decide if the current
 // thread name has changed. We combine all the seen thread names into the
 // output name for the thread.
 LazyInstance<ThreadLocalPointer<const char> >::Leaky
     g_current_thread_name = LAZY_INSTANCE_INITIALIZER;
 
 const char kRecordUntilFull[] = "record-until-full";
 const char kRecordContinuously[] = "record-continuously";
 
@@ skipping 687 matching lines @@
     }
   }
 #if defined(OS_ANDROID)
   ApplyATraceEnabledFlag(category_enabled);
 #endif
   return category_enabled;
 }
 
 void TraceLog::GetKnownCategories(std::vector<std::string>* categories) {
   AutoLock lock(lock_);
-  for (int i = 0; i < g_category_index; i++)
+  for (int i = g_num_builtin_categories; i < g_category_index; i++)
     categories->push_back(g_categories[i]);
 }
 
 void TraceLog::SetEnabled(const std::vector<std::string>& included_categories,
                           const std::vector<std::string>& excluded_categories,
                           Options options) {
   AutoLock lock(lock_);
 
   if (enable_count_++ > 0) {
     if (options != trace_options_) {
@@ skipping 441 matching lines @@
         0,                       // num_args
         NULL,                    // arg_names
         NULL,                    // arg_types
         NULL,                    // arg_values
         TRACE_EVENT_FLAG_NONE);  // flags
   }
 }
 
 }  // namespace trace_event_internal